I'm quite surprised, I didn't expect my musical taste to be similar to that many people here..
soooo...in order how they pop in my mind..
Black Sabbath (up till 1982) + Heaven And Hell (in fact Black Sabbath's 1981-2 lineup in disguise)
AC/DC
Led Zeppelin
Joe Satriani
Iron Maiden
Queen (well, not as much fond of their later, more 'pop' sound with a lot of synths - but I like some of those too)
Pink Floyd (with the exception of the early post-Barrett era when the band was experimenting with sound too much, and also Final Cut...I don't really like Waters, feels too political for my taste)
The Who
Deep Purple
Guns N' Roses
Ozzy Osbourne (with Zakk Wylde as guitarist)
Faithless
The Ramones
Jimi Hendrix
Hammerfall
Nightwish
The Darkness
Them Crooked Vultures
Van Halen
Sex Pistols
Lily Allen
David Bowie
Gotthard
The Raconteurs
Kiss
Van Halen
Mot?rhead
uhhhhhhhh and a lot of particular songs by bands and singers mostly from the 'old school rock' era, including Beatles, Rolling Stones, Eric Clapton, The Yardbirds, Lynyrd Skynyrd, ZZ Top, Jefferson Airplane, The Doors, Kinks, Steppenwolf, CCR, and numerous others (either I like only certain songs or I haven't gone through their discographies yes)
Also a number of movie soundtracks I think my favorite composers would be Hans Zimmer (although he tends to get quite repetitive), John Williams, Jerry Goldsmith an I can't remember the rest..oh yea, Danny Elfman for example
Classical music? Yeah, like it too but haven't listened to anything lately.
Sometimes I listen to electronic stuff like trance mainly while playing something like FPS or racing games..
Recently I also grew fond of the album Skeletons in the Closet by Children of Bodom, although I do find this band 'too heavy for my liking', but this album is made entirely of cover versions and it's really fun to listen to.
And although most of my fave bands fall under rock/metal genre, when I like something, I don't actually care about genres.
Duh, and I probably forgot a ton of stuff I like, anyway.